This is classic data mining at work. Even if each scale purchaser only made one other drug-related purchase, when you look at the clusters, the pattern becomes obvious.

Amazon clearly did not set out to create such a field-tested kit for starting an illicit business. But looking at the list of items, it sure seems like they've created a group of products by looking at the purchasing habits of people who may not be recording all of their incomes on W-2s and 1099s. Not everyone who buys one of these scales is a drug dealer, but... it sure seems popular among a demographic in need of baggies.

So, how long until police departments find an AWS-100 scale and request account information from Amazon?

The digital-rights advocacy group, EFF, has dinged Amazon's terms of service for its lack of transparency around how they cooperate with law enforcement: "The service is not making clear to their users what standards and rules law enforcement must follow when they seek access to sensitive user data."

Privacy, such as it is on the web, is collective. Beware who you share purchases or click-patterns with.